Building Regulations Thermal Building Regulations

Thermal Building Regulations - England & Wales

Building Regulations – Conservation of fuel and power

Building Regulations Approved Document L (AD L) comprises four Approved Documents:

• AD L1A for New dwellings

• AD L1B for Existing dwellings

• AD L2A for New buildings other than dwellings

• AD L2B for Existing buildings other than dwellings

With specific reference to AD L1A for New Dwellings, compliance is based on the carbon performance of the whole dwelling, a measure of which is given through the use of the Standard Assessment Procedure (SAP calculation). Compliance is no longer demonstrated by the elemental U-value method, but U-value calculations are required as they form part of the SAP calculation. Although reference is made to ‘Design Limit’ U-values within AD L1A, U-values better than the ‘Design Limit’ are likely to be required to meet the required Carbon index level.

AD L1B for Existing dwellings includes extensions, creating new dwellings through material change of use and material alterations to existing dwellings. Whilst compliance is still based on carbon dioxide emissions, U-values to the levels detailed in the tables below should be met.

Where an existing element forms part of the thermal envelope it must have a certain thermal value. This is known as the ‘threshold’ value. If the existing value of the element equals or is better than the threshold, no thermal renovation will be required. If it is worse than the threshold value then thermal renovation to achieve the values in the table below will be required.

AD L2A for New buildings other than dwellings is based on carbon performance of the whole building. A calculation process has to be followed and the Simplified Building Energy Model (SBEM), developed by the Building Research Establishment (BRE), is the methodology for carrying out these calculations.

AD L2B for Existing buildings other than dwellings. Whilst compliance is still based on carbon dioxide emissions, U-values to the levels detailed in the tables below should be met.

Where an existing element forms part of the thermal envelope it must have a certain thermal value. This is known as the ‘threshold’ value. If the existing value of the element equals or is better than the threshold, no thermal renovation will be required. If it is worse than the threshold value, then thermal renovation to achieve the values in the tables below.

Thermal Building Regulation U-Values

Thermal Building Regulations - Scotland

New building Regulations were introduced in Scotland in 2010 covering:

• health, safety, welfare of people within and around buildings
• conservation of fuel and power
• achievement of sustainable development.

Guidance on complying with the requirements of the regulations is given in two Technical Handbooks, one covering domestic buildings and the other non-domestic buildings. Each Handbook has seven sections, including Section 0 which is common to both Handbooks and covers common general issues.

Sections 1 to 6 give guidance on how to achieve the standards set by the regulations, and there are different sets for domestic buildings and non-domestic buildings. The six sections each cover a number of related standards. They are:

• Section 1 Structure
• Section 2 Fire
• Section 3 Environment
• Section 4 Safety
• Section 5 Noise
• Section 6 Energy

Section 6 – Energy

The standards and guidance given in this section are intended to reducing emissions of carbon dioxide by approximately 30% compared to the 2007 standards. The key changes over the 2007 version are:

• 30% improvement in CO2 emissions for new buildings
• New requirement covering heat loss from party walls
• Expanded role for the use of low carbon equipment
• Improved backstops for fabric U values and services efficiencies for new buildings
• Guidance on improving energy performance in existing buildings introduced

Section 6 includes a range of measures which can be used in setting the target emission rate for a notional dwelling. Included are guideline “notional” U values, as follows:

Existing Buildings

Section 6 also addresses work on existing buildings, including conversions & extensions, as follows:

N.B. All U-Values are area weighted.